Sputtering device

ABSTRACT

This invention is a sputtering device comprising at least: a vacuum container defining a vacuum space; a substrate holder installed rotatably in said vacuum space; a substrate installed on said substrate holder; a target for forming thin film on said substrate; and a rotatable sputtering cathode in which said target is installed, wherein said sputtering cathode is slant to said substrate, and a center of said target is eccentric to a rotation axis of said sputtering cathode.

BACKGROUND OF THE INVENTION

The present invention relates to a sputtering device which has a target for forming a thin film on a substrate and in which ionized gas is collided to the target in order to sputter atoms or molecules of the target and the atoms or the molecules are stuck on the substrate to form the thin film on the substrate.

A sputtering device disclosed in JP 2002-20864 A is that three plates with same constitution for modifying distribution are arranged between three targets and a circular shaped substrate, a rotation center of rotated substrate is made offset from a center of the target at a specific distance and the substrate and the target are arranged so as to radiate sputtering particles obliquely to the substrate.

JP 2003-247065 A discloses a device for forming thin film that particles of materials for forming film are sputtered from a plurality of sputtering sources by using ions of plasma flow in order to form thin film on the substrate. As the device generates plasma due to electronic cyclotron resonance discharge by a means for generating plasma, symmetrical rotation axes of the plural sputtering source targets are crossed on a rotation center axis of a sample substrate base and arranged so as to incline to the rotation center axis of the sample substrate base. Besides, the sample substrate base is provided with a rotation means for rotating slantly so that a crossing point of the symmetrical rotation axes of the targets and the rotation center axis of the sample substrate base is positioned in an opposite side of the target against a sample substrate for forming thin film, and a moving means for moving the sample substrate base up and down.

In the devices disclosed in the above JP 2002-20864 A and JP 2003-247065 A, though sputtering target materials must be set to specific positions in order to gain not more than ±3% of film evenness desired usually, a problem so that setting positions are different by kinds of the sputtering target materials is arisen. However, if a range between 1 to 3% of forming film distribution is desired, it is possible to gain available positions between the substrate and the sputtering target materials by repeating experimentation, but not more than 1% of the forming film distribution by increase of device functions is desired recently, so that response to the request becomes difficult. Besides, in the case that the forming film distribution desired in a market is achieved by setting available positions between the substrate and the target materials, change of the forming film distribution by using repeatedly can not be followed recently because the sputtering target materials are consumed.

SUMMARY OF THE INVENTION

An object of the invention is to provide a sputtering device which can gain a stable forming film distribution.

Accordingly, the present invention is a sputtering device comprising at least: a vacuum container defining a vacuum space; a substrate holder installed rotatably in said vacuum space; a substrate installed on said substrate holder; a target for forming thin film on said substrate; and a rotatable sputtering cathode in which said target is installed, wherein said sputtering cathode is slant to said substrate, and a center of said target is eccentric to a rotation axis of said sputtering cathode.

It is preferred that the sputtering cathode comprises at least a means for cooling provided behind the target, magnets for generating magnetic field to the target and an earth shield arranged around the target, and is rotatable by a rotation means.

Furthermore, it is preferred that an extending line of the rotation axis of the sputtering cathode and an extending line of a rotation axis of the substrate holder cross at an approximate center position of the substrate.

Accordingly, the target which is arranged so as to slant to the substrate and rotated can be sputtered according to the present invention, so that the forming film distribution can be designed so as to be uniformed.

Furthermore, because adhesion rate for forming film is increased, productivity can be increased.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a sputtering device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED WORKING MODE

Hereinafter, a working mode of the present invention is explained by referring a drawing.

A sputtering device 1 according to an embodiment of the present invention is, as shown in FIG. 1, constituted of at least a vacuum container 3 defining a vacuum space 2 inside thereof, a substrate 5 installed on a substrate holder 4 which is arranged in the vacuum space 2, a target 6 arranged so as to face to the substrate 5, and a sputtering cathode 7 in which the target is installed.

A vacuum pump not shown in the figure is connected to an exhaust vent 10 of the vacuum container 3, so that the vacuum space 2 is formed by exhausting air inside thereof. Besides, a gas introducing vent 11 for supplying gas such as argon gas to the vacuum space 2 is provided in the vacuum container 3. The gas introducing vent 11 is opened or closed by a valve 12 suitably.

The substrate holder 4 is supported in the vacuum space 2 by a rotation shaft 4b which is held rotatably to the vacuum container 3, and rotated by an electric motor 4c.

The sputtering cathode 7 is arranged so as to be slanted at a specific angle to the substrate 5 and has a rotation axis B which is eccentric to a center axis A of the target 6. An electrode base 13 is provided around the rotation axis B. An earth shield 14 is provided via an insulator 15 so as to surround the electrode base 13. Magnets 20 are arranged via sealing for vacuum behind a base support 16 on which the target 6 is installed. Cooling water is supplied via a feed pipe 17 a and a drain pipe 17 b in order to prevent heat increasing of the target 6 behind the base support 16. Besides, the electrode base 13 is connected to one terminal of a sputtering power source 18 and another terminal of the sputtering power source 18 is connected to the vacuum container 3. Note that the sputtering power source 18 is a DC source or a high frequency power source. Furthermore, the sputtering cathode 7 is rotated by a driving motor 19. Besides, the sputtering cathode 7 is arranged so that an extending line of the rotation axis B of the sputtering cathode 7 and an extending line of a rotation axis C of the substrate holder 4 cross at an approximate center of the substrate 5, and the center axis A of the target 6 rotates around the rotation axis B by rotation of the sputtering cathode 7.

According to the above mentioned constitution, the substrate 5 for thin film to be formed is installed on the substrate holder 4, the vacuum space 2 is formed inside the vacuum container 3 by exhausting air, the substrate holder is rotated at a specific speed, gas for sputtering is introduced inside the vacuum space 2, high voltage is applied between the sputtering cathode 7 and the substrate 5, sputtering particles are sputtered from the target 6, and then the sputtering cathode is rotated at a specific speed to the substrate 5, so that the thin film is formed on the substrate 5.

Thus, since the target 6 is revolved to the target 5, an angle of incidence of the sputtering particles can be changed, so that good thin film distribution and coverage distribution can be achieved. Accordingly, because the best forming film distribution can be always gained, it can contribute to stability in mass production. 

1. A sputtering device comprising at least: a vacuum container defining a vacuum space; a substrate holder installed rotatably in said vacuum space; a substrate installed on said substrate holder; a target for forming thin film on said substrate; and a rotatable sputtering cathode in which said target is installed, wherein said sputtering cathode is slant to said substrate, and a center of said target is eccentric to a rotation axis of said sputtering cathode.
 2. A sputtering device according to claim 1, wherein: said sputtering cathode comprises at least a means for cooling which is provided behind said target, magnets for generating magnetic field to said target and an earth shield which is arranged around said target, and is rotatable by a means for rotation.
 3. A sputtering device according to claim 1, wherein: an extending line of said rotation axis of said sputtering cathode and an extending line of a rotation axis of said substrate holder cross at an approximate center position of said substrate.
 4. A sputtering device according to claim 2, wherein: an extending line of said rotation axis of said sputtering cathode and an extending line of a rotation axis of said substrate holder cross at an approximate center position of said substrate. 